Been working on a survival dungeon crawler as a side project. So far I have:
1.) Survival stats linked to the hud. Stats give detriments when reached. For example at 35% rest you will lose strength stats, and max hp. At 0% you will lose 1/2 of both. For hunger and thirst when you reach 0% you will lose health until you die.
2.)Working lantern that uses oil, and usage is linked to the hud. If it runs out of oil the lamp turns off. You can refill it with oil flasks, which give you back an empty bottle when used.
3.) If you die, you drop your souls on the ground, and a physical soul is represented where you died in the game world. If you die before picking up these souls, they will disappear and you will drop your current souls at your most current location of death. (Yes this is a direct ripoff of dark souls, I love the mechanic.)
4.)Node based world map travel
5.)Weight system. Everything has weight, and if you are overburdened you cannot hold any more. Also adds infinite storage to your house.